January : Named after Janus, the Roman god of gates, doorways, beginnings, and endings.
March : Named after Mars, the Roman god of war
May : Possibly from the Roman goddess Maia, wife of Vulcan
June : Possibly named after Juno, the queen of the gods in Roman mythology.
Monday : Its name is from the Moon, which is derived from the Norse god of the moon, Mani, who would pull the moon through the sky every night while being chased by Hati.
Tuesday : Derived from Tyr, the Norse god of war
Thursday : Derived from Thor, the Norse god of thunder, as well as the son of Odin and Jord.
Friday : Derived from Frige, the love goddess of Norse mythology, and also the wife of Odin.
Saturday : From Saturn, a Roman agriculture and harvest deity